Browsing by Subject "prebiotic"
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Item Evaluation of the Dairy/Yeast Prebiotic, Grobiotic-A, in the Diet of Juvenile Nile Tilapia, Oreochromis niloticus(2012-02-14) Peredo, AnjelicaTwo different feeding trials were conducted to evaluate the effects of dietary supplementation with the dairy/yeast prebiotic GroBiotic-A (GBA) to Nile tilapia diets. A nutritionally complete basal diet was supplemented with GBA at either 1 or 2% of dry weight, and all three diets were fed to triplicate groups of juvenile fish in two consecutive trials. Trial 1 continued for 8 weeks, while Trial 2 was conducted for 5 weeks to more specifically assess immunological responses, intestinal characteristics and disease resistance of tilapia. At the conclusion of Trial 1, there were no differences in weight gain (WG) or feed efficiency (FE) among fish fed the three diets. However, fish fed the diet with GBA at 2% had significantly increased survival and noticeably elevated levels of plasma lysozyme compared to fish fed the basal diet or the diet with GBA at 1%. Similarly, at the conclusion of Trial 2, WG and FE were unaffected by GBA supplementation; however, fish fed the diet with GBA at 2% also exhibited elevated plasma lysozyme as well as significantly (P < 0.05) increased levels of extracellular superoxide anion production (EX-SOAP) by macrophages. Dendrogram analysis of denaturing gradient gel electrophoresis (DGGE) images detected a significantly different microbial community within the intestine of fish fed the diet with GBA at 2% compared to fish fed the basal diet and diet with GBA at 1%. None of the experimental diets resulted in significant improvements to survival after exposure to Streptococcus iniae due to within treatment variability. However, fish fed the diet with GBA at 2% did tend to experience reduced mortality (12.5%) as compared to fish fed the basal diet (35%). Thus, supplementation of GBA at 2% of diet did alter the gut microbiota of tilapia and enhanced immunological responses and disease resistance to S. iniae.Item Prebiotics Have Limited Effects on Nutrients Digestibility of a Soybean-Meal-Based Diet by Goldfish Carassius auratus(2011-02-22) Raggi, ThiagoPrebiotic compounds comprise a group of dietary supplements defined as nonviable food ingredients that are selectively metabolized to favor beneficial intestinal bacteria. Such bacteria may confer various desirable effects including enhanced disease resistance and nutrient availability to the host. This study examined the effects of four prebiotics, GroBiotic?-A (a mixture of partially autolyzed brewers yeast, dairy ingredient components and dried fermentation products), mannanoligosaccharide (MOS), galactooligosaccharide (GOS), and the fructooligosaccharide (FOS) inulin on digestibility of soybean-meal-based diets by goldfish. A basal diet was formulated so that 50% of the protein was provided by soybean meal and the other 50% was from menhaden fishmeal. Each prebiotic was supplemented to the basal diet at 1% by weight. A diet containing all of its protein from menhaden fish meal also was prepared as a control diet. Chromic oxide was added to the diets at 1% as an inert marker. Each diet was fed to adult goldfish in duplicate 110-L iv aquaria for a total of 8 weeks. The dried fecal material from each aquarium was pooled over time and analyzed for protein, lipid, organic matter and chromium in order to compute coefficients of apparent digestibility. Genomic DNA of gut microbiota also was isolated from the fecal samples of goldfish fed the various diets and subjected to polymerase chain reaction (PCR) using bacteria-specific PCR primers to conserved regions flanking the variable V3 region of 16S rDNA. Then, denaturing gradient gel electrophoresis (DGGE) of the resulting amplicons was conducted as a means of assessing diversity of microbiota in the gastrointestinal (GI) tract. Results of the present study revealed that none of the prebiotics affected apparent digestibility coefficients of the soybean-meal-based diet compared to the basal diet, although the diet supplemented with MOS consistently yielded the lowest values. In addition, goldfish digested the soybean-meal-based diets as well as the control diet. DGGE analysis revealed no differences in microbiota of goldfish fed the various prebiotics. These results are in contrast to those obtained with carnivorous fish species such as the red drum (Sciaenops ocellatus) in which the prebiotics increased digestibility coefficients of soybean-meal-based diets and altered GI tract microbiota.